Bob, That formula for torque applies to an electric motor. The torque produced BY the motor. You cannot transfer that formula over to a non electric pulley. Open the link below. It shows % torque as it relates to % speed. You will note that at 100% rpm (1750 rpm in this case) the torque is 100% (3 ft-lbs typical for a 1hp motor). Now using our shredder, the shredder pulley is spinning at 200 rpm, or about 10% of the motor. So, looking at the chart we see the torque at the shredder pulley is about 10% or about .3 hp.
The transmission analogy only holds water if we are talking about geared systems but in this case we are talking pulley/belted systems.
I think I'm about ready to go back to talking about tobacco. Anyone else care to join me?